Communication racks and relay racks are used in communication rooms to manage voice and data lines at demarcation points between carriers and users, or at other points in a network. A typical communication rack has two upright rails upon which a number of patch panels and other related electronic devices, such as hubs or routers, are mounted to connect one set of lines to another. The rails are separated by standard distances depending on whether it is a data rack (19 inches) or a telecommunication rack (23 inches). The rails can be exposed, or they can be enclosed in a cabinet or another enclosure to provide better control of the moisture and temperature surrounding the electronic devices. As one example of such a rack, a plurality of patch panels are commonly mounted on the rails of the communication rack to connect an outside line (e.g., a T1 line) from a carrier with a number of individual lines.
A typical patch panel includes a flange for mounting the patch panel to the upright rails of the communication rack, a back panel having one or more horizontal rows of ports for receiving incoming lines, and a front panel having a plurality of jacks for receiving outgoing lines. Each jack in the front panel corresponds to a port in the back panel. The flange projects from the sides of the patch panel to overlap the rails, and the flange has a number of mounting holes corresponding to a pattern of fastening locations along the rails. The patch panel can be mounted to the rack at a selected elevation by aligning the mounting holes of the flange with the fastening locations on the rails at the desired elevation, and then attaching the patch panel to the rails with a plurality of fasteners. A number of panels can be stacked vertically in this manner.
The back panel of the patch panel has a number of ports for receiving the individual lines that have been separated out of a complex line, such as a T1 line. The ports are organized in horizontal rows, and each row commonly has 24 ports. Depending on the number of individual lines that are to be connected to the patch panel, the back panel may have one, two or three rows of ports. A patch panel having three rows of ports is known as a three-unit (3U) patch panel, and it occupies approximately 5.25 vertical inches of rack space. A two-unit (2U) device has two rows of ports and occupies approximately 3.5" of vertical rack space. Likewise, a one-unit (1U) device has one row of ports and occupies approximately 1.75" of vertical rack space.
The front panel of the patch panel has one or more horizontal rows of jacks that correspond to the rows of ports on the back panel. Outgoing cables are easily connected to and disconnected from the appropriate jacks on the front panel to couple lines connected to the back panel to desired devices. Thus, as the individual devices are moved to different locations throughout a building, the devices may be coupled to the same lines on the back panel by switching the outgoing cables to the appropriate jacks of the front panel.
In operation, a first group of patch panels commonly manages the primary lines coming into a communications room, and a second group of patch panels manages the secondary lines going to specific locations in a building. By systematically connecting a patch cord between a specific jack of the first group of patch panels and a selected jack of the second group of patch panels, one line can be connected to another line in the building. The patch cords projecting from the jacks on the first patch panel are routed to another location on the rack or to another rack to be connected to the second patch panel.
A number of problems exist with current systems for managing cables in communication racks. As a general matter, most communication cables may not perform efficiently if they are crimped or bent tighter than a minimum bend radius. This is particularly true with fiber optic cables because sharp bends affect the optical properties of the cables. For example, in 3U patch panels in which the rows of cables hang from the patch panel, the collective weight of the stacked cables causes the lower rows of cables to bend at a tighter radius than the upper rows of cables. The lower rows of cables may consequently experience cross-talk or other problems. To prevent this from happening, installation technicians often mount each patch panel to a rack to provide enough vertical space above and below the patch panels to run the cables between the patch panels. As a result, a typical communication rack with approximately 48U of total space will have between 20U and 30U of space used for cable management and only about 18U-28U of space occupied by patch panels or other equipment.
A significant problem with this type of cable management system is that the vertical rack space occupied by the cables reduces the number of patch panels and other electric devices that can be mounted to the rack. The additional number of lines required for fax machines and modems is just exacerbating this problem causing communication racks to quickly fill to capacity. For example, because conventional cable management techniques required 20-30U of vertical rack space for supporting the cables, many communication racks are already at full capacity and cannot hold additional electronic devices. In many applications, therefore, the installers must purchase new racks or even build a larger communications room. Thus, conventional cable management techniques can present significant problems for businesses and other users that need to reconfigure or install new communications equipment.
Futhermore, merely using additional vertical rack space for adding new patch panels is difficult when the cables hang vertically in front of the patch panels and completely obstruct the technician's view of the front of the rack. To insert additional patch panels, technicians must sometimes disconnect cables. Disconnecting cables, however, is highly undesirable because it interrupts phone or data lines, and it creates a risk that the line will be incorrectly reconnected. Debugging a complex communications rack is complicated and time-consuming, and can be extremely expensive. Thus, reconfiguring or otherwise retrofitting communication racks that have some excess capacity is also difficult.